What's The Difference Between CRO and SEO Split Testing?

February 15, 2023
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Digital marketing is all about continuous improvement. Getting more traffic, clicks, or conversions does not happen without effort, and marketers must keep testing and optimizing brands' pages to see results. Split or A/B testing lets marketers see whether their proposed tweaks will improve their app, email sequence, or website. Digital marketers use two different types of tests—CRO- and SEO-focused testing.

CRO testing creates page variations, and SEO testing uses only one version of each page, separating the pages into a control group and a variable group. CRO tests measure how these changes affect users' behavior, and SEO tests examine how the adjustments affect traffic and rankings. Here is a closer look at each type of test.

What Is Conversion Rate Optimization?

As the name implies, CRO maximizes the chances that people will fulfill the CTA on your pages. It tests variables to see which ones will increase the number of visitors who sign up for your mailing list, request a demo, or complete a purchase. CRO is when you create page variations and assign users to either the control or experimental kind.

How Do You Conduct a CRO Test?

It helps to divide CRO testing into stages. First, identify the pages that are not performing well. You can get this from your web analytics dashboard or CRM systems. Next, you can conduct surveys and focus groups for qualitative data on why these pages are not performing as well as they should. After these, you can create your conversion-centric hypotheses and roll out page variants that will test these.

During the test, when a visitor lands on a page, they see either the experimental or the control page. The browser cookie ensures that the one they first see will be the one they keep seeing if they leave and come back to the site.

After you gain the data you need, you can segment the traffic to see how it affected the outcome. A statistically significant hypothesis, one where the experimental page has more conversions, means you can proceed with a rollout. If conversions drop significantly for the experimental page, you know to avoid these changes in the future.

Why Should You Implement CRO Testing?

There are various benefits to CRO testing. When you conduct a CRO test, you gain data that can guide your insights. Instead of making assumptions about your audience and implement something with no scientific basis, you have concrete proof that a strategy could work for your market, that it can attract people you're targeting.

Testing your hypotheses before implementing changes throughout your site lets you build a safety net for adverse effects on your traffic. Conducting a CRO test allows you to contain the drop in conversions, which means you don't waste resources on changes that harm your website or ones that produce no apparent benefits.

Implementing changes that show a positive effect on conversion rates could improve all of your marketing efforts. Since CRO testing proves that your strategy works on existing traffic, it could affect all sorts of traffic, whether organic, paid, email, or social. As such, these results can bring down your CPA and improve your revenue, which means more profits.

What Is SEO A/B testing?

Though CRO and SEO testing use roughly the same processes, they have very different goals. Conversion optimization aims to raise visitors' chances of following through with the CTA once they get onto the site. Meanwhile, SEO testing is about finding ways to increase the number of visitors. This kind of test is great for websites with multiple pages, like e-commerce or real estate, because it needs several pages to form test groups.

Instead of creating two types of pages, SEO split tests separate a group of pages or 'shoes' into 'trainers' and 'heels.' The pages designated as trainers are the experimental group, while heels are the control group. The marketer implements changes on the trainers and keeps the heels the same. 

For instance, suppose you're testing whether the proposed (left-hand side) or your current (right-hand side) image location is more appealing to your audience. Your 'trainers' group will have images on the left-hand side, while the 'heels' group will have them on the right. Note that these are groups of pages with different information but have the same template.

You need to run SEO tests in this manner so you can avoid duplicate pages. Duplicates can hurt test results; since Google penalizes duplicate content, you will get an inaccurate picture of the page's capacity to drive traffic. When you split up identical groups of pages into control and experimental groups, you can focus on the effects of technical changes. You can isolate the factors that directly contribute to the increase (or decrease) in traffic.

How Do You Know If An SEO Test Is Successful?

Check if your tests were successful by comparing both the control and the experimental group against the traffic forecast. If the experimental group does better than the forecast and the control pages don't, the changes could have been the reason for the change. If this is the case, you can implement the change on all the other pages.

What Else Should You Know About SEO Testing?

Like with any marketing strategy, there are downsides to SEO A/B testing. For one, it takes a lot of time. Brands often find it difficult to sustain the resources needed to carry out a full SEO A/B test. If you are on a tight budget, you can implement changes without hiring developers if you use edge computing or maximize the Content Delivery Networks. You can apply changes to cached versions of your website when you do this. If the changes statistically improve traffic, you can implement them to your entire website.


Marketing is not something you only do when you have to promote a new product or service. It is a continuous process that involves engaging your audience and reminding them of your brand. If you are not seeing traffic to your website, you could implement a split or A/B test to see what you need to improve, and always test your results to see how you can do better!

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